The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Motorized vehicles may include a powertrain that includes a powerplant (e.g., an engine, an electric motor, and/or a combination thereof), a multi-speed transmission, and a differential or final drive train. The powerplant produces drive torque that is transmitted through one of various gear ratios of the transmission to the final drive train to drive wheels of the vehicle.
Hybrid powerplants may include a combination of an engine and one or more electric motors that supply drive torque to the transmission. The transmission may be an automatic transmission and may include one or more planetary gear trains for transmitting the drive torque. Planetary gear trains generally comprise a sun gear, a planetary carrier with pinion gears, and a ring gear. The sun, pinion, and ring gears are in meshing engagement and are capable of outputting several gear ratios. Planetary gear trains require two inputs to obtain a predictable gear ratio. The inputs may be selectively provided to any two of the sun gear, planetary carrier, pinion gears, and ring gear.
For example, holding the ring gear stationary while the sun gear engages with the planetary carrier produces a reduction (i.e. lower gear ratio). Alternatively, holding the sun gear stationary while the ring and planetary pinion gears mesh produces an overdrive (i.e. higher gear ratio). Additionally, holding the planetary carrier stationary while the sun, pinion, and ring gears mesh produces a reduction and a reversal of the direction of rotation.
One input may be the drive torque supplied by one or more components of the powerplant. A second input may be provided by a clutch assembly that is coupled to one of the components of the planetary gear train, typically the ring gear. The clutch assembly may input a grounding torque that inhibits rotation (e.g., hold stationary) of one of the components of the planetary gear train. The clutch assembly may include one or more actuators for grounding the clutch assemblies.